1 
   2 /*
   3  * Copyright (c) 2016, Red Hat, Inc. and/or its affiliates.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #ifndef SHARE_VM_GC_SHENANDOAH_SHENANDOAHFREESET_HPP
  26 #define SHARE_VM_GC_SHENANDOAH_SHENANDOAHFREESET_HPP
  27 
  28 #include "gc/shenandoah/shenandoahHeapRegionSet.hpp"
  29 #include "shenandoahHeap.hpp"
  30 
  31 class ShenandoahFreeSet : public CHeapObj<mtGC> {
  32 private:
  33   ShenandoahHeapRegionSet* _regions;
  34   CHeapBitMap _free_bitmap;
  35   size_t _max;
  36 
  37   // Left-most and right-most region indexes. There are no free regions outside
  38   // of [left-most; right-most] index intervals
  39   size_t _leftmost, _rightmost;
  40 
  41   size_t _capacity;
  42   size_t _used;
  43 
  44   void assert_bounds() const PRODUCT_RETURN;
  45   void assert_heaplock_owned_by_current_thread() const PRODUCT_RETURN;
  46 
  47   bool is_free(size_t idx) const;
  48 
  49   HeapWord* allocate_small_memory(size_t words_size, ShenandoahHeap::AllocType type, bool& in_new_region);
  50   HeapWord* allocate_large_memory(size_t words_size);
  51 
  52   HeapWord* try_allocate_in(size_t word_size, ShenandoahHeap::AllocType type, size_t idx, bool& in_new_region);
  53   HeapWord* allocate_single(size_t word_size, ShenandoahHeap::AllocType type, bool& in_new_region);
  54   HeapWord* allocate_contiguous(size_t words_size);
  55 
  56   void adjust_bounds();
  57 
  58   void increase_used(size_t amount);
  59   void clear_internal();
  60 
  61   size_t count()    const { return _free_bitmap.count_one_bits(); }
  62 
  63   bool implicit_live(ShenandoahHeap::AllocType type) const;
  64 public:
  65   ShenandoahFreeSet(ShenandoahHeapRegionSet* regions, size_t max_regions);
  66 
  67   void add_region(ShenandoahHeapRegion* r);
  68   void clear();
  69 
  70   size_t capacity()  const { return _capacity; }
  71   size_t used()      const { return _used;     }
  72   size_t available() const {
  73     assert(_used <= _capacity, "must use less than capacity");
  74     return _capacity - _used;
  75   }
  76 
  77   HeapWord* allocate(size_t words_size, ShenandoahHeap::AllocType type, bool &in_new_region);
  78   size_t unsafe_peek_free() const;
  79 
  80   void print_on(outputStream* out) const;
  81 };
  82 
  83 #endif //SHARE_VM_GC_SHENANDOAH_SHENANDOAHFREESET_HPP